The concept of tic was developed at the end of the XIX century, emerging from the "chaos of choreas". Tic is defined as involuntary contractions of agonist and antagonist muscles in one or more parts of the body. It can be suppressed by voluntary efforts for seconds or hours, followed by exacerbations. Gilles de la Tourette's original article was published in 188S, in which he described nine patients with tics, and vocalisations.The pathogenesis of Gilles de la Tourette syndrome remained obscure. However, three factors have been considered: the neurochemical factor, related to the increased dopaminergic activity at the basal ganglia; the genetic factor and the non-genetic factors, for which environment more than genetic factors are involved. Pathologic examinations failed to reveal structural lesions, but PET studies showed metabolic hypofunction on the frontal, cingulate and possibly insular cortex, and on the inferior corpus striatum. The motor tics as well as the vocal tics can be simple or complex and are present in all patients. Other signs can be added to the previous tics: sensory tics, echophilia, coprophilia, obsessions, compulsions and impulsions. Diagnostic criteria of Gilles de la Tourette syndrome are based on: age of onset; presence of motor and vocal tics; voluntary suppression of the movements; variation in number, type, location and severity of tics; duration of more than one year. Haloperidol is the drug of choice for the treatment of Tourette's syndrome.